diff --git a/src/Makefile b/src/Makefile
index 1a36c60..b7adb3e 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -60,7 +60,7 @@ C_SOURCES=foundation_pEp_jniadapter_Engine.cc \
     throw_pEp_exception.hh \
     foundation_pEp_jniadapter_AbstractEngine.h
 
-PEP_HEADER:=$(shell $(CXX) -E -M get_header.cc | grep -oe '[^[:space:]]*pEpEngine\.h' | head -1)
+PEP_HEADER:=$(shell $(CXX) $(CXXFLAGS) -E -M get_header.cc | grep -oe '[^[:space:]]*pEpEngine\.h' | head -1)
 
 
 .PHONY: all
diff --git a/src/get_header.cc b/src/get_header.cc
index 561c863..d713295 100644
--- a/src/get_header.cc
+++ b/src/get_header.cc
@@ -1 +1 @@
-#include "pEpEngine.h"
+#include <pEp/pEpEngine.h>